Mold



Aug.' 26', 1941; F. HAGEMEYER 2,253,905

MOLD

Filed Aug. 2, 1958 2 sheets-*sheet 1 I "N 7@ gi?? I l 77 75 '"I V I Y :l76" 79 I 'u M 73 @in I I NVE NTo R HEAWFFMEMM ATTo RN EY Aug 26,1941- IH. F. HAGMEYER 2,253,903

M LD I Filed Aug- 2, 19:58

mm I linlr ATTORNEY Patented Aug. 26, 1941 A e UNITED slii'ras a Mou)Henry F. Hagemeyer, Chicago, Iii., assignor to Castings Illinois PatentCorporation, a corporation of A application August z, 193s., serial No.222,599A

My invention relates to methods and apparatus fon-controlling thetemperature of metal which has been poured into a mold in a castingoperation and more particularly to such methods and apparatus forexpediting the cooling of the poured metal in a controlled manner,whereby the characteristics of the metal in the ,casting may beregulated.

In conventional casting practice cooling of the poured metal is usuallyuncontrolled, so that, 'as the heat is dissipated, the temperature indiiferent parts of the casting will vary according to the body of suchparts. ,By body I mean the relative sizes of the variouscomponentportions of the casting. 'Ihus a part of large body or sizewill cool more slowly than a 'smaller one.. for all parts oi' thecasting are subjected to apy proximately the same temperaturedifferential andv are substantially equally insulated from. the latmosphere. Such difference in cooling rate occurs. of course, becausethe larger sectionshave less heat radiating surface in proportion totheir volume and heat content 4than have the smaller sections. As themetal in the casting solidifles and cools shrinkage takes place. so thatadditional metal tends to now toward the solidifying parts from portionsof the casting which are still fluid, to compensate for the deficiencycaused by such shrinkage. If there are no adjacent fluid sections, aswhere a liquid pocketor central section is solidifying, sunken. portionson the surface of the casting or internal shrinkage faults may result,which are undesirable.

By the employment of my controlled cooling method the order ofsolidification of the various portions of the casting may bepredetermined to avoid leaving fluid pockets or centers whollysurrounded by set metal, the feeders supplying-the deficiency caused bythe `metal shrinkage. Within the term feeder I include the usual gatethrough which the metal enters the casting cavity, as well as risers,shrink pins, or shrink bobs which may be provided on portions of thecasting remote from the gate. Thus there will be no internal shrinkage-in the casting, tendirg to make internal fissures, or sunken portionsin the metal surface, for the vshrinkage^deilciency of all solidifyingportions will be replaced successively from the next portions tosolidify, and the last portions of the castingto solidify `will befilled from reservoirs of molten metal formed byl such feeders outsideof the casting proper. 'I'he essence 6f my process lies in controllingthe cooling so that the portions of the casting most remote fromthefeeder will solidify rst, and

thereafter portionsprogressively. nearer to the f connection of` afeeder with the casting will remote from the feeder connection asnecessary to obtain progressive solidiiication oi the various parts inthe sequence above stated.

vAnother type of mechanism m embody a hollow cooling member, the cham rof which contains a cooling medium either at rest or as a liquid owingtherethrough. In the latter case the rate of flow through the coolingmember may be thermostatically controlled, the flow volume varying`accindfng to the temperature of the cooling fluid.d Also 'the course ofthe fluid over the castingmay be arranged so that the flow will betoward the feeder connection, that is, from the Darts to be cooled mostquickly toward the parts to be cooled at a less rapid rate, thetemperature differential between the fluid and the `metal therebyprogressively decreasing in the direction of flow. A further variationof cooling rate may be obtained by regulating the ilow quantity o fcooling fluid so that the volume flowing over the portions'of thecasting to be cooled most rapidly is greater than \the volume flowingvover other'portion'sof the casting. Such a volume control may becombined with a ilow course toward the feeder connection, if desired,portions of the cooling fluid being tapped oif at inter- 40'vals alongthe `course to produce the (proper quantity variation.

The principal object of' my invention, therefore, is to obtain acontrolled coolingl of a casting-within a mold, so that the portionsmost remote from the connection of a feeder with the casting will besolidified and cooled first and the `size of the variing proper will ineach case be entirely solidiiied,

and cooled as much as possible, .prior to the solidication of a feederor feeders connected therewith, so that deficiencies of metal in thecasting caused by the shrinkage which takes place during suchsolidification and cooling may be replaced from the still fluid feedersinstead of from a surface of the casting, causing a depression therein,or from the interior of the casting, creating internal flaws andfissures.

.An additional object of my. novel method is not only to control theLcooling of acastingso that the parts thereof will -be solidified in adesired sequenceLbut also to control the r-ate at which the variousparts are cooledin order to obtain desired grain structure and physicalcharacteristics in the cast metal.

It is also desired to accomplish the aforementioned objects' bymechanism of simple though effective design, which may be readilyadapted to y carry out my cooling `method on castings of al wide varietyof shapes and sizes.

Specifically it is an object to provide appropriate `cooling fins,specially proportioned molds, or supplementary artificial coolingAmechanism,

A or a combination of these features, most suited lto -the propercooling of a particular casting in the manner desired. i y

More specific objects, inherent in the examples of mechanism shown inthe drawings, will be understood from the following description thereof.The drawings illustrate the application of my method to, and the use ofapparatus in carry-` v bledl mold and associated mechanism, illustratedcooling apparatus combining a plurality of exwill not have internalshrink faults or surface depressions even when cast without specialcooling control, because the metal will naturally solidify from the endfarther from the gate, which is poured first. The same natural properdirectional sol-ldification will occur unassisted where the castingtapers from the size of the gate outward. the solidification progressingfrom the end v most remote from the gate toward the connection of thegate with the cavity, and the gate will be the last to become solid, sothat deficiencies caused by the metal shrinkage in the casting may l bereplaced from the gate. Few castingsare of these types, however, andwhere the gate or other feeder Ais of smaller cross section than theportion of the casting to which it is joined, as is usually the case,the metal in the feeder tends to solidify before the metal in thecasting, thus cutting o nection will be caused to solidify first@Thereafter, parts progressively nearer the feeder connections will inturn solidify and this order of solidiflcation will be preservedregardless of the castings shape, or variation in body, that is., eitherthickness or width or both, of the severall portions of the casting.

In cooling anaircooied airplane engine cylin-vl der head casting,lsuchas shown in Figs. 1 and 2, iinsuid cooling mechanism, and a shell moldmay all be employed. In this instance the fins,

instead of beingadded especially to carry out pedients employedseparately in the previous iigures.

Fig. 2 is a transverse sectional view taken along line I-i of Fig. i.

In the casting of metal the general practice heretofore has been toprovide a sprue, a runner, and risers if necessary, positioned anddimensioned only to obtain complete filling of the mold cavity. There'has been no effort to proportion the runner or riser to have a definiterelationship to -the size or shape of the casting to be produced for thepurpose of maintaining such feeder fluid until the casting is completelysolidified. Despite the insulating quality of the -moldmaterialtherefore, the feeders and their I ing therefrom toward the centerof'the casting,

If these defects are to be avoided, the metal in -the feeder or feedersand their connections with the casting must remain liquid until all themetal of the casting proper has solidified, so

that the feeders may actas reservoirs to make up for the 4shrinkagedeficiency in the casting. A bar' casting of thesame size as ythe gateent, unless a very thick mold wall is employed to minimize the heatradiating eii'ect of the hns.

`S, since the cross section of the casting increases fairly uniformly tothe connection of the sprues therewith. The only diiiiculty might be inthe, tendency of the sprues S to solidify prior to completesolidii'ication of the heavy casting, in which case internal shrinkageor a sunken the rocker boxes might result.

In this particular type of casting, however, the fins are required as avital, integral part of the finished casting. l The provision of fins onthe exterior of this casting without additional artificial coolingmechanism not only tends to set up strains caused by the unequal coolingresurface on suiting from the greater heat radiation surface afforded bythe fins, but also tends to cool more ausm -I 1 ance the cooling actionof the exterior una if trolled cooling sequence. While in theapplication of my cooling method to some castings the heat may beremoved in a controlled manner almost entirely from one side onlythereof because of the thinness of the metal, this procedure will notoperate satisfactorily upon a thick walled casting such as the cylinderhead shownv in Fig. 1. The reentrant portion of the skirt Il would notsolidify until after solidiilcation of the finned rocker boxes 'H hadcut olf. passage therethrough for fluid metal from the sprue B to theskirt 1l, to compensate for metal shrinkagel therein. A sunken surfacewithin the skirt and dome would result. It is therefore necessary tprovide articial cooling mechanism both for'the interior and for theexterior surfaces of the skirt 10, so that Vit will be solidifiedcompletely before the axial parts of the rocker boxes 'Il solidify.

In cooling the cylinder head according to my method I prefer to lemploymetal formera Il which are'insertediwithin the reentrant portion of theskirt 1 and may be spaced therefrom as shown in Fig. 1. This interveningspace is filled with an annulus of mold material gradually in- .creasingin thickness from the edge of the skirt arranged in the verticaldirection. their formation would be diillcult.- I prefer, therefore. touse a core incorporating metal cooling formera as described. Since thecast metal contracts in cooling, the cavity likewise will becomesmaller. and to prevent fracturing the vcasting by resisting suchcontrastive stress. the formera Il encircling the cavity are yieldablyFour such'formers may conveniently be employed, as shown in Fig. 2.Between the adjacent edges and ends of these formers should be placedsome crushable substance, such as mold material which toward the centralportion of the dome. Because the plurality o'f fins provides somuch-heat radiating surface it may be necessary to use additional meansfor expediting the removal of heat from the inner surface. such ascooling fluid flowing through passages llfin the formera. The' directionof iiow should be as indicated by,the arrows in Fig. lrthe fluidyflowing i'lrst past the skirt llil and being warmed asitilows toward thesprue or feeder connection. the warmest uid being discharged from theformera near their upper ends through pipes 14, which may all unite in amay be of th'e gypsum base type. capable of yielding under the stresscreated by the Icontracting cylinder head skirt. No appreciableresistance to the contraction of the cast metal will therefore boffered, so that no strains will be developed in the casting as would bethe case if the core were of rigid construction. The members 12.supported on plate I'L may slide substantially unrestrainedly away fromthe mold supporting plate under thepressure of the shrinking cast metal.Pivoted levers 1l, suspended from a mold form base plate 1l, may ,beprovided, which engage the bases of the formera 12, for use in drawingthem from the casting cavity after the metal has solidified. Suchwithdrawalmay be made at any temperature desired after solidification toallow further cooling to take' place more slowly without using theartificial cooling means of the core,

or the cooling may bedelayed bypassing hot v fluid through the passages1l. Within the circle of for'mers a thin wall of mold material may beemployed to support their backs. as shown, if

necessary to enable the core-to withstand the force of theinrushing'metal without deformat I tion.

header I5 discharging into an outlet conduit Il 40 where gypsum basemolds of sumcient porosity having therein a thermostatic valve Theoperation of this complete mechanism will -eiiect proper directionalcooling, because the combined action of the skirt fins on the outsidewith the fluid and metal cooling means on the inside will cause rapidvsolidiflcation ofthe skirt from its edge toward its base. 'I'he uns onand between the rocker boxes il will hasten their solidlnca-A tion, butthis will not be complete prior to the l entire soudincauon or the skirtand dome poralthough completely surrounded by solidified portions, suchiluid pockets causing shrinkage faults upon solidication, thesolidincation .of the4 entirecasting will be progressive from the edgeof the skirt 10 upward to the bases of the rocker boxes and thence totheir upper ends. All the solidi-.- ncation in the casting will takeplace while the sprues S lare still inthe fluid state lo that they willserve as reservoirs from which metal may be supplied throughout theentire solidiiicationfof the casting, to compensate for the deficiencyof metal in the casting cavity caused by the shrink. 'age of thesolidiiying metal.

As has been stated, the iins which expedite cooling vof the exteriorwall of the casting are formed as part of the finished While temporaryuns might be provided in the reentrant portion of-the cylinder headskirt to bal- This process may be used in either sand or plaster moldingoperations. but it is most useful to allow the pouring gases to seepthrough the mold body are used. Every riser added for a shrinkagereservoir requires additional pattern expense,.an excessive amount ofcasting metal,

and necessitates additional machining in the nnishing operation. With myprocess applied to a porous gysum molding operation, ordinarily the onlyexterior reservoir of molten metal will be the'gate, runner and spruearrangement which is a necessary provision in every case. If for anintricate casting an additional feeder is foundto be necessary when mydirectional cooling process is employed, several more feeders would benecessary if my process were not used, one for each part or the castingwhere animated molten pocket would occur in natural cooling. Henceconsiderable expense is eliminated, as well as a better productobtained. by the use of my procf ess, and castings can be made where itis employed which could `not be produced without flaws if such processwere not used.

As my invention, I claim:

In a moldhaving therein a cavity for casting an internal combustionengine cylinder head; the

combination of a centrally pertured base plate supporting the mold, aplurality of rigid metal members projecting upward through the baseplate aperture in laterally spaced relation. mold material covering/saidmembers to form areentrant wall for the casting cavityl and further moldmaterial interposed between adjacent members, means supporting saidmembers from said base plate for individual lateral movement withrespect thereto toward the center of its aper- 4 :,asspcs ture underpressure of the cast metal shrinking sages therethrough, an individualcooling liquid during cooling, a lever for each of said mem'bers supplyconduit connected to each ot said mem pivoted upon said base plate andengaging the bers, a common discharge manifold for said lower end o! itsmember for withdrawing it at members and thermostatic means controllingthe will from the mold through the aperture in said 5 discharge ofcooling iiuid from said manifold. base plate, said rigid metal membershaving pas- A HENRY F. HAGEMEYER.

